I like to contemplate artist Nancy Holt's Sun Tunnels near Lucin, Utah as a time and light engine. Her work is simple and complex. It is as simple as its four concrete tubes or tunnels. And its complexities include the work's X alignment that line up with summer and winter solstices' sun. Furthermore, each tunnel’s auxiliary openings are patterned after the Draco, Perseus, Columba and Capricorn constellations, and all year round the sun and moon cast such a variety of shadows and light patterns because of all the tunnel openings.

“Time is not just a mental concept or a mathematical abstraction in the desert,” Holt says. “The rocks in the distance are ageless; they have been deposited in layers over hundreds of thousand of years. Time takes on a physical presence.”